ANM19/15
International Association of Marine Aids to
Navigation and Lighthouse Authorities
Formerly ANM18/WG1/WP6
IALA Guideline No. 1081
On
the Provision of
Virtual Aids to Navigation
AISM Association Internationale de Signalisation Maritime IALA
Edition 1.?
20ter, rue Schnapper, 78100
Saint Germain en Laye, France
Telephone: +33 1 34 51 70 01 Fax: +33 1 34 51 82 05
e-mail: iala-aism@wanadoo.fr
Internet: www.iala-aism.org
Guideline 1081 – Virtual Aids to Navigation
March 2010
DOCUMENT REVISIONS
Revisions to the IALA Document are to be noted in the table prior to the issue of a revised
document.
Date
Page / Section Revised
Page 2 of 22
Requirement for Revision
Guideline 1081 – Virtual Aids to Navigation
March 2010
TABLE OF CONTENTS
DOCUMENT REVISIONS
2
TABLE OF CONTENTS
3
INDEX OF TABLES
4
VIRTUAL AIDS TO NAVIGATION
5
1
INTRODUCTION
5
2
SCOPE
5
3
PURPOSE
5
4
DEFINING A VIRTUAL AID TO NAVIGATION
5
4.1
Definition
5
4.2
Amplification
5
5
5.1
5.2
6
6.1
USE OF VIRTUAL ATON
6
User needs
6
5.1.1
6
Advice to Mariners
Benefits
7
APPLICATION OF VIRTUAL ATON
7
Technical deployment
7
REGULATORY ISSUES
7
7.1
Authority to deploy
7
7.2
Capability
8
7.3
Liability
8
7
8
8.1
8.2
DELIVERY METHODS
8
Technical aspects
8
DISPLAY
8.2.1
8.2.2
8.2.3
8.2.4
8.2.5
9
General
Limitations
Symbols
Point and Area Representation
Expiry and cancellation of Virtual AtoN objects
9
9
9
9
10
9
NOTIFICATION
10
10
RISKS AND LIMITATIONS
10
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Guideline 1081 – Virtual Aids to Navigation
March 2010
10.1
Risk Mitigation
11
10.2
Limitations
12
10.2.1
10.2.2
10.2.3
10.2.4
12
12
13
13
11
GNSS vulnerability
Spoofing and Jamming of Virtual AtoN
AIS VDL capacity and FATDMA planning
Display Limitations
LEVEL OF SERVICE
13
11.1
Availability
14
11.2
Integrity alerting
14
11.3
Continuity
14
12
DEVELOPMENT CONSIDERATIONS
14
13
REFERENCES
16
14
ACRONYMS / INITIALISMS
18
ANNEX 1 Application of Virtual Aids to Navigation
INDEX OF TABLES
Table 1
Potential risk mitigation measures
Page 4 of 22
11
Guideline 1081 – Virtual Aids to Navigation
March 2010
VIRTUAL AIDS TO NAVIGATION
1
INTRODUCTION
IALA recognises that there are various tools available for use by aids to navigation authorities to
improve and enhance services to mariners. Among these are visual aids, radio aids and now,
virtual aids to navigation.
This document offers national members and other authorities guidance on the provision of
virtual aids to navigation.
2
SCOPE
This document provides guidance on the use of virtual aids to navigation (Virtual AtoN), risks
and benefits, criteria for application, notification process, display, application and delivery
methods, applicable standards and guidelines, availability and integrity, legal and liability issues.
This document is a general guide only and is not intended to specify in detail when or how to
deploy Virtual AtoN. Appropriate sources (see references) should be consulted for additional
relevant information.
The concept of Virtual AtoN has its roots in AIS but in the future other means of transmission
and presentation will evolve. References to AIS in this document should not be construed as
limiting Virtual AtoN to that system.
3
PURPOSE
The purpose of this Guideline is to inform aids to navigation authorities, mariners and
equipment manufacturers of the value and uses of Virtual AtoN. It will assist administrations
and authorities in determining the appropriate uses for and the means to establish and operate
virtual AtoN. This Guideline will assist shipmasters, pilots and other mariners in realizing the
benefits, limitations and the inherent risks involved when using virtual AtoN as a means to verify
their position, determine a safe course to steer or to avoid dangers. This Guideline will assist
marine electronics equipment manufacturers in designing and marketing the next generation of
shipboard navigation display systems. Finally, maritime training institutes may also wish to avail
themselves of the information contained herein in order to develop syllabii that will prepare
seafarers to take advantage of this emerging technology.
4
4.1
DEFINING A VIRTUAL AID TO NAVIGATION
Definition
A virtual aid to navigation (Virtual AtoN) does not physically exist but is a digital information
object1 promulgated by an authorised service provider that can be presented on navigational
systems after approval of a national competent authority.
4.2
Amplification
Virtual AtoN can be used to inform the mariner about dangers to navigation as well as safe
waterways, areas in which extra caution may be necessary and areas to be avoided.
They may be used to represent a line, area, position or other form that may be displayed
graphically.
1
An item or group of items, regardless of type or format that a computer can address or manipulate
as a single object that will inform the user as to the characteristic of a Virtual AtoN.
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Guideline 1081 – Virtual Aids to Navigation
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The information, including geographic position, carried by virtual AtoN may be fixed or may be
changed over time (dynamic), depending on the intended purpose.
Virtual AtoN are used primarily where there is a time critical consideration. They may also be
used in places where permanent physical aids to navigation cannot be sited or maintained.
However, they are not intended to replace physical aids to navigation.
There are two applications of virtual AtoN, temporary and permanently. They should be
reflected in Maritime Safety Information (MSI) and be shown on the relevant nautical paper
chart, ENC and other relevant nautical publications in due course.
5
APPLICATION OF VIRTUAL AtoN
Virtual AtoN can provide early notification to the mariner of urgent, temporary or dynamic
information. Virtual AtoN should not, in general, be considered as a replacement for other
forms of MSI but can provide a valuable supplementary delivery mechanism, enabling an
automated graphical display of MSI otherwise only available in textual form. In certain
circumstances, virtual AtoN can be also used as permanent marking. Specific applications are
described at the Annex 1 of this Guideline.
User needs
Users will include mariners and shore side authorities.
User needs may include presentation of information on:












5.1.1
New hazards (fixed or dynamic);
Temporary channels or routes;
Temporary areas to be avoided (e.g. survey / dredging/ fishing / yacht racing);
Changed hydrography;
Temporary replacement of off station physical AtoN;
Dynamic areas (e.g. reduced visibility, presence of protected species);
Polar navigation;
Ice conditions and navigation;
Incident response (e.g. environmental, SAR);
Port specific applications (e.g. passage planning, amended pilot boarding location,
etc.);
Measures for the protection of the marine environment;
Security.
Advice to Mariners
In using Virtual AtoN the following are among the issues that need to be considered:








Avoidance of reliance on single sources of information;
Refer to MSI;
Be aware of the possibility of different symbols on different systems;
Be aware of limitations of Virtual AtoN provision and presentation;
Difference between Virtual, Synthetic, Real AIS AtoN (A-126);
The need to maintain situational awareness by comparing electronic and nonelectronic means;
The need to avoid target fixation;
Many systems, including AIS, are GNSS dependent for position and timing and
subject to the same vulnerabilities.
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March 2010
5.2
Benefits
Some of the potential benefits of Virtual AtoN in enhancing safety, environment and security
are:








6
Timely notification;
Ease and accuracy of presentation, where displayed graphically;
Ease and speed of deployment;
Direct delivery to navigational systems; limited to relevant area;
Information readily apparent to the user;
Avoidance of misinterpretation through use of standardised symbology and IMO
phraseology;
Easily changed / amended;
Low cost to install and maintain.
TECHNICAL DEPLOYMENT OF VIRTUAL AtoN
Information from the Virtual AtoN services should be broadcast to shipboard receivers by more
than one means. The navigation information provided for virtual AIS AtoN must be repeated in
MSI broadcasts to assure that all mariners receive safety information. Virtual AIS AtoN
messages should include a reference to identify the associated MSI message. Reference could
be provided in the Message 21 field ‘Name of AtoN Extension’. (see Reference [19]) ‘The
‘Name of AtoN Extension’ needs to be considered on a wider scale when developing new
message definitions for Virtual AtoN delivery. (See section 8.1)
The navigation information needs to be displayed on ECDIS, ECS and on radar equipment.
These displays should indicate the information graphically as well as provide text display of
detailed information when available in addition to the graphic.
There may be a limit to the number of Virtual AtoN and / or their reporting interval (update rate),
that can be in the same area due to limitations in the capacity of the communication link. There
may also be a limitation on the shipboard processing capability.
To mark areas, AIS binary application specific messages may be used, rather than multiple
Virtual AIS AtoN (Message 21). There is a limit to the number of Virtual AIS AtoN that can be in
the same area due to available timeslots in the AIS system. Multiple virtual AIS AtoN (Message
21) could increase clutter on the display. The authority needs to be aware that the number of
Maritime Mobile Service Identities (MMSI) available for use by AIS AtoN is a finite resource
(1000 per designated area code) and for this reason another means of unique identification,
linking Virtual AtoN to relevant MSI or chart objects may need to be considered in the future.
MMSI numbers are normally assigned to a transmitting device. For virtual AIS AtoN using
Message 21, the MMSI number represents the unique identity of the AtoN itself, rather than the
transmitting source. The repeat indicator is used to identify whether the signal is transmitted
from another station.
7
7.1
REGULATORY ISSUES
Authority to deploy
SOLAS Chapter V Regulation 13 (Establishment and operation of aids to navigation) states, in
part, that “each Contracting Government undertakes to provide, as it deems practical and
necessary, either individually or in co-operation with other Contracting Governments, such aids
to navigation as the volume of traffic justifies and the degree of risk requires.”
Under SOLAS, Contracting Governments are obliged to provide aids to navigation, subject to
IALA Recommendations and Guidelines and based on the navigational requirements for waters
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Guideline 1081 – Virtual Aids to Navigation
March 2010
under their jurisdiction. However, SOLAS allows administrations significant discretion in
determining what would be an appropriate mix of visual, radio and now virtual aids to navigation
to meet the needs of mariners.
Section 10 of this document is intended to assist administrations to assess the risk associated
with Virtual AtoN for this purpose.
7.2
Capability
A Contracting Government has an obligation under SOLAS to provide aids to navigation. This
obligation is exercised by the appropriate entity (usually a national administration). This entity
should also be responsible for determining who may be permitted to deploy virtual aids to
navigation. Typically, a VTS, Harbour Master, Rescue Co-ordination Centre (RCC) or some
other entity may have the capability to deploy virtual aids to navigation.
The lines of authority between the Contracting Government and the entity deploying virtual aids
to navigation should be clearly delineated. Roles and responsibilities at all levels should be
clearly defined.
7.3
Liability
Virtual aids are simply another type of aid to navigation. Having elected to deploy a virtual aid,
an administration should be able to establish that the virtual aid is being provided as
promulgated and is operating correctly.
It is likely that an administration’s exposure to liability from deploying a virtual aid will be similar
to that for any other aid to navigation. Therefore, noting the unique nature of virtual aids to
navigation, robust processes and procedures for promulgating information about them, together
with integrity monitoring and record keeping, should be established.
8
8.1
DELIVERY METHODS
Technical aspects
This guideline addresses near term and long term alternatives for delivery of a Virtual AtoN
service.
In the near term, shore based AIS networks provide competent authorities with means to
operate an information service for shore-based VTS, traffic management schemes, ship
reporting systems and other shore-based safety-related services, including Virtual AtoN
services. This service consists of information delivery between ships and shore and vice versa.
Technical details of the AIS technology and of the layout and local configuration of shore-based
AIS are described in IALA Recommendation A-124.
In the longer term, authorities may expect that other media for information services will become
available. This would enable Virtual AtoN services to be transmitted via means other than AIS,
for example: satcom/internet; WiMAX; LORAN; DGPS - IALA maritime beacon system; GPRS
cell phone data transmission protocol.
In the near term, not all vessels can be expected to be able to effectively display Virtual AtoN
information. As of July 2008 SOLAS Radars are required to interface to AIS and display AIS
information, as in MSC Resolution 192(79). Although ECDIS is capable of displaying AIS
information, it is not required to do so. Based on current rates of navigation system upgrades, it
is expected to take at least ten years before 50% of the international commercial fleet will have
this capability. Changes in mandatory carriage requirements may accelerate this development
for SOLAS vessels.
Portable Pilot Navigation Systems may facilitate implementation.
Economic benefit to the shipping industry could also provide an impetus to early adoption of this
new technology.
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Guideline 1081 – Virtual Aids to Navigation
March 2010
The nominal report rate of Virtual AtoN AIS broadcasts is specified in ITU-R-M.1371. However,
due to the limitations in data link capacity IALA Recommendation A-126 recommends a more
flexible approach to be considered, taking data link capacity and power consumption at
transmitting stations into account.
In the longer term, different report rates may be implemented on different communication
media, as appropriate.
The IMO e-Navigation concept includes the need to harmonise the presentation of both
shipboard and shore side safety related information. Consideration should be given in
implementing Virtual AtoN to the harmonisation process within e-Navigation for future
applications.
8.2
8.2.1
Display
General
The Virtual AtoN should clearly indicate by its name or other relevant attribute the related
navigational warning, notice to mariners or other form of MSI relating to the provision of the
object.
The display or representation of symbols for Virtual AtoN onboard should be standardised. The
display of symbols ashore should align to the onboard standard as closely as possible, to
facilitate a common interpretation of the maritime situation. (see Reference [24])
8.2.2
Limitations
In the short to medium term Virtual AtoN will not be visible on the displays of many ships and, if
visible, the symbols may differ from one display to another (see section 10.2).
8.2.3
Symbols
IMO SN/Circ. 243 Annex 2 provides guidance on the use of navigation related symbols on all
shipborne navigational systems and equipment. The symbol for AIS AtoN is a diamond with a
cross at the position of the AtoN, as follows.
No distinction is made between real and Virtual AtoN. These navigation related symbols are not
chart symbols2.
In IEC 62288 (Navigation Displays) and IEC 62388 (Radars) that came into force in 2008, the
diamond is specified for AIS AtoN. For Virtual AIS AtoN the diamond has a V inside. This
symbol will be implemented as an overlay on navigation equipment (ECDIS, radar etc)
compliant with these specifications. Currently the symbols do not indicate the type of AtoN,
although display equipment may allow interrogation to obtain such information.
The ECDIS performance standard requires that overlay symbols should be readily
distinguishable from chart symbols. Chart symbols for Virtual AtoN are under development by
the IHO based on the existing chart symbology for AtoN.
It should be noted that colours for the use of Virtual AtoN symbols are not clearly stated for
ECDIS overlay and radar display in current specifications.
8.2.4
2
Point and Area Representation
Navigation related symbols are approved and adopted by IMO. Chart symbols are approved and
adopted by IHO.
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In addition to the use of the AtoN Report Message 21, emerging application specific messages
could be used to provide a representation of a point position, line, area, or other form that may
be displayed graphically. There is a need to develop appropriate methods of representation,
clearly distinguishable from existing charted symbols.
8.2.5
Expiry and cancellation of Virtual AtoN objects
Some Virtual AtoN objects (like the AIS AtoN Message 21) rely on repeated transmission to
remain valid – however current display standards are not clear on this issue, and
implementation may therefore vary in the short to medium term. The timeout limit of a
repeatedly transmitted Virtual AtoN must be defined in future standards, in order to ensure that
the same information is available to all users at all times. (The IEC 62388 radar standards
defines when AIS class A and B vessel targets are lost – approximately when the nominal
repetition rate has been exceeded by a factor of 6. This general rule is recommended to be
implemented for the display of Virtual AtoN in future display standards.)
Some Virtual AtoN objects (like the emerging application specific messages) may themselves
contain a definition of their own lifetime – time of issue and time of expiration. These Virtual
AtoN objects – and Virtual AtoN objects relying on repeated transmissions with repetition, but
with a long timeout – should be accompanied by a mechanism for cancellation, in case they
become obsolete during their defined lifetime or contain errors. Such a cancellation mechanism
also constitutes a mitigation measure to ensure that erroneous or malicious transmissions can
be cancelled.
When the lifetime of a Virtual AtoN object is timed out or cancelled, it should be removed from
display systems. Objects relying on repeated transmissions that have exceeded the nominal
reporting rate, but have not yet reached the timeout should, when queried for additional
information, clearly indicate that the information may not be up to date.
9
NOTIFICATION
Having elected to deploy Virtual AtoN, administrations should arrange for detailed information
related to such aids to be made available to all concerned.
Administrations should use all available means to ensure that mariners have the necessary
information concerning the presence and purpose of virtual aids, including the intended duration
of deployment. These means may include MSI broadcast via NAVTEX, INMARSAT Enhanced
Group Call (EGC) or VHF/HF/MF radio. The administration should send specific notification to
their hydrographic offices for inclusion in notices to mariners and should correct and update
relevant paper charts, electronic charts and nautical publications.
As with other aids to navigation, mariners have an obligation to report malfunctioning virtual aids
to navigation to the competent authority.
10
RISKS AND LIMITATIONS
The Virtual AtoN are not visible on the displays of many ships and, if visible, the symbols may
differ from one display to another. The consequences may be confusion, lack of information for
the user and the undermining confidence in ECDIS, the chart and other systems. It is likely to
take at least a decade to harmonise the provision of Virtual AtoN as a result of the ’grandfathering‘ clauses in the carriage requirement program for ECDIS and the likely schedule for the
adoption of IBS & e-Navigation.
Radar will only display Virtual AtoN as an overlay of a diamond with a V inside if they are
compliant with IEC 62388. This test specification came into force in 2008. At the current rate of
fitting new equipment, 10-15 years appears to be a realistic timescale for the majority of ships to
benefit from the provision of display of Virtual AtoN.
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Navigational displays compliant with IEC 62288, which came into force in 2008 will show Virtual
AtoN as an overlay of a diamond with a V inside.
ECDIS equipment fitted prior to 2009 will not show Virtual AtoN until the equipment is upgraded
or replaced, which is unlikely under the current “grand-fathering” arrangements. There is
currently no provision for Virtual AtoN in S-57, or a symbol in S-52, but this is capable of
implementation. However, even when Virtual AtoN are reflected in S-57 and S-52, existing
ECDIS will only show an orange “?” upon encountering a Virtual AtoN object in the ENC
database. The orange “?” can be interrogated for further detail.
The Minimum Keyboard Display (MKD) should display AIS AtoN, including the virtual flag, but it
is known that some MKDs do not meet this requirement.
10.1
Risk Mitigation
Table 1
Potential risk mitigation measures
Risk
Potential Mitigation
Not all mariners will receive or be able to MSI should be maintained as primary system,
display Virtual AtoN
Virtual AtoN supplements MSI
Encourage
integration
displays, where fitted
with
navigation
Development of e-Navigation and S Mode
Information overload
Use of lines and areas versus points
Only competent authorities may approve issue
Area specific display
Development of e-Navigation
Limited use of Virtual AtoN in any area
Lack of user awareness or understanding
Training
Clear promulgation of information
Develop educational material
Confusion from varying symbology
Standardisation of symbology by IMO, IHO,
IALA, IEC.
Equipment may be set up not to show data
Instruction and training
S Mode
Confusion from message options for locations,
area and lines
IMO / IALA to define message formats
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Risk
Potential Mitigation
Loss of signal
Published standards for availability, continuity,
integrity
Verification of transmission by originator
Redundancy
Integrity warning
Correlation with MSI and / or chart
GNSS vulnerability
AIS semaphore mode
Satellite monitoring / RAIM
DGNSS integrity message
Electronic terrestrial backup
Virtual AtoN vulnerability; jamming / spoofing
Verification of transmission by originator
Correlation with MSI and / or charts
Data link monitoring by authorities
Counter-spoofing (cancelation methods)
No confirmation of receipt of message
Repeated or
transmissions
addressed
/
acknowledged
Verification of transmission by originator
Multiple transmission paths (MSI)
Development of e-Navigation
Erroneous message transmitted
Procedures for message checking
Verification of transmission by originator
Dynamic prediction accuracy i.e. floating Estimation of zone of uncertainty
object
Updated verification
Remove position from message after time
10.2
10.2.1
Limitations
GNSS vulnerability
Ships may lose their positioning capability when the GNSS service is lost due to jamming or
interference, unless they have an alternative positioning system. Poor installation or failure of
on board equipment can similarly interfere with or degrade GNSS reception.
Delivery of a Virtual AtoN Service through the AIS VDL would not necessarily be affected
immediately by loss of GNSS, since the position part of the message is fixed and transmitted
independent of GNSS.
10.2.2
Spoofing and Jamming of Virtual AtoN
Depending on the media, a Virtual AtoN service can be spoofed and jammed easily. Jamming
can be unintentional or intentional while spoofing would typically be intentional.
Some spoofing methods can be detected through careful monitoring of the transmission
channel. One possibility is to monitor MMSI numbers within the service coverage area.
Duplicated or non-existing MMSI numbers within the coverage area may indicate spoofing.
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Increased spoofing detection capability can be achieved through regional co-operation between
neighbouring countries, exchanging valid MMSI numbers and co-operating on identifying invalid
MMSI numbers, for example handing over MMSI numbers from one authority to another
authority when vessels crossing the administrative boundaries of these authorities. Such a
scheme is implemented on the administrative boundary between the Malacca and Singapore
straits.
Authorities who provide Virtual AtoN services should maintain a database of all valid MMSI
numbers assigned to Virtual AtoN. This database should be shared with such stakeholders as
neighbouring countries.
Both spoofing and jamming can compromise and/or shut down a Virtual AtoN service. Jamming
will typically block the service in a certain geographic region. Spoofing is more sinister since the
targeted receiver cannot detect the deception (i.e. the signal appears to be genuine), which
could mislead the navigator.
10.2.3
AIS VDL capacity and FATDMA planning
Virtual AtoN services transmitted on an AIS VDL typically use the FATDMA protocol.
If the population of Virtual AtoN in a given area is too high, this may overload the VDL FATDMA
slot capacity.
This should be overcome through careful FATDMA planning (IALA
Recommendation A-124 refers).
10.2.4
Display Limitations
Although there are clear benefits that can be gained by providing safety information through
Virtual AtoN, it must be borne in mind that very few SOLAS class ships, or other craft, may have
the ability to display the Virtual AtoN. Some craft may never have the ability to display Virtual
AtoN.
MKD – All SOLAS class vessels are required to be fitted with Class A AIS station and many non
SOLAS vessels voluntarily carry Class A AIS or Class B AIS stations. However, currently, few
vessels integrate the AIS data into a navigation display such as ECDIS or Radar. The display
of Virtual AtoN on an AIS Minimum Keyboard Display (MKD) is limited to alpha-numeric text
and, on some units, a graphic display, although there is no standard for such display.
Radar – Only radars that meet the revised performance standard, which came into force in
2008, have a requirement to be capable of displaying a Virtual AtoN. However there is currently
no requirement for the AIS to be integrated or displayed on the Radar.
ECDIS – ECDIS mandatory carriage requirement for certain classes of SOLAS vessels is being
implemented from 2012 – 2018, however the current ECDIS performance standard MSC
232(82) does not require AIS or other Virtual AtoN to be able to be displayed, nor to be
integrated.
Administrations should take into account the limited display capabilities for AIS, or other forms
of transmission, for all classes of seaborne craft when assessing the value and risks associated
with transmitting Virtual AtoN.
11
LEVEL OF SERVICE
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11.1
Availability
The basic principles for categorising AtoN in accordance with their importance is described in
Recommendation O-130 (IALA Category 1, 2, or 3). Virtual AtoN Services should be
categorised in the same manner.
If a transmitting site is transmitting signals for multiple Virtual AtoN, the most critical one would
determine the availability requirements for the service. It should be noted that Virtual AtoN
transmitting sites must deliver a specified minimum signal strength at the user antenna within a
specified service area.
IALA Recommendation A-126 defines the required availability for AIS Virtual AtoN and sets the
service area criteria in terms of required signal strength.
Similar signal strength criteria should be defined for transmissions transmitted via means other
than AIS.
Availability is determined by the ability to deliver the specified reporting rate, signal strength and
valid information content. Virtual AtoN criteria should be specified for each of these elements in
order to clearly define when the service is no longer available (failure state).
11.2
Integrity alerting
Authorised service providers should have the ability to provide users with warnings within a
specified time when a Virtual AtoN service is not available.
The warning should be given within a time frame compatible with the criticality of the AtoN (IALA
Categories 1, 2 and 3).
Warnings may be issued as MSI and, in the case of AIS, using the flags of message 21, using
message 14 or by any other appropriate means.
There is a requirement for integrity monitoring. Such monitoring schemes should be
independent of the system providing the basic service. Integrity monitoring can take place both
onboard a vessel and ashore.
Shipborne monitoring is limited to validity checking of the received datagram and the reporting
rate of the Virtual AtoN.
11.3
Continuity
Continuity is the probability that, assuming a fault-free system at the receiving end, the Virtual
AtoN will be received and displayed on the navigational display over the time interval applicable
for a particular operation.
The continuity of a Virtual AtoN service should be determined as described in Recommendation
R-121. The time interval should be chosen as 3 hours, or a suitable time frame as determined
by the authority providing the service.. The probability should be according to the category
(IALA categories 1, 2 and 3) of each Virtual AtoN. If a transmitting site is transmitting signals for
multiple Virtual AtoN, the most critical one would determine the continuity requirements for the
service.
12
DEVELOPMENT CONSIDERATIONS
For the full benefits of Virtual AtoN to be realised, a number of issues must be addressed in
consultation with other bodies, including:


appropriate instruction and training of all mariners and providers as to the provision
of Virtual AtoN, symbology, display, and limitations;
harmonisation of integration and ship navigation system specification to enable the
display of Virtual AtoN for SOLAS ships and other users;
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Guideline 1081 – Virtual Aids to Navigation
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


a strategy for implementation of Virtual AtoN using non-AIS based systems;
the harmonisation of the use of MSI by Virtual AtoN within the context of the IMO’s
e-Navigation concept;
harmonised presentation of Virtual AtoN.
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13
REFERENCES
[1]
IMO Res. A.917(22) 2001 Guidelines for the Onboard Operational Use of Shipborne AIS
[2]
IMO Res. A.956(23) 2003 Amendments to the Guidelines for the Onboard Operational
Use of Shipborne AIS
[3]
MSC 232(82) Performance Standards for ECDIS
[4]
MSC.192(79) Performance standards for radar equipment
[5]
MSC.191(79) Performance Standards for the Presentation of Navigation-Related
Information on Shipborne Navigational displays
[6]
MSC 86/23/7 New symbols for AIS-AtoN - Submitted by Japan
[7]
IMO SN/Circ 243 – Amendments to Guidelines for the Presentation of Navigation-Related
Symbols, Terms and Abbreviations
[8]
IMO SN/Circ 266 Maintenance of ECDIS Software
[9]
IMO SN/Circ 289 Guidance of the Use of AIS Application Specific Messages
[10] IMO SN/Circ 290 Guidance for the presentation and display of AIS Application Specific
Messages Information
[11] ITU-R M.1371 Technical Characteristics for Automatic identification System using Time
Division Multiple Access in the VHF Maritime Mobile Band
[12] IHO S-4 Chart Specifications of the IHO and Regulations for International (INT) Charts
[13] IHO S-52 Specifications for Chart Content and Display Aspects of ECDIS
[14] IHO S-57 Transfer Standard for Digital Hydrographic Data
[15] IHO S-57 Appendix B.1 ENC Product Specification
[16] IHO S-100 Universal Hydrographic Data Model
[17] IHO S-101 ENC Product Specification (ENC Product Specification based on S-100 (not to
be adopted before 2012 at the earliest))
[18] IALA Recommendation R-121 For the performance and monitoring of a DGNSS Service in the
band 283.5 – 325 kHz
[19] IALA Recommendation A-124 IALA Recommendation A-124 on Automatic Identification
System (AIS) Shore Station and Networking Aspect relating to the AIS Service
[20] IALA Recommendation A-126, on the Use of the Automatic Identification System (AIS) in
Marine Aids to Navigation Services, Edition 1.4, Dec. 2008
[21] IALA Recommendation O-130 on Categorisation and Availability Objectives for Short
Range Aids to Navigation
[22] IALA Recommendation O-133 Emergency Wreck Marking Buoy
[23] IALA Guideline 1062 on the establishment of AIS as an Aid to Navigation
[24] IALA Recommendation V-125 on the Use and Presentation of Symbology at a VTS Centre
(including AIS)
[25] IEC 61174 ECDIS – Operational and Performance Requirements, Methods of Testing
and Required Test Results
[26] IEC 61193-2 Class A shipborne equipment of the universal automatic identification system
(AIS) - Operational and performance requirements, methods of test and required test
results AIS Class A
[27] IEC 62288 Presentation of navigation-related information on shipborne navigational
displays
Page 16 of 22
Guideline 1081 – Virtual Aids to Navigation
March 2010
[28] IEC 62320-2 AIS AtoN stations - Minimum operational and performance requirements methods of test and required test results
[29] IEC 62388 Maritime navigation and radio-communication equipment and systems –
Shipborne radar - Performance requirements, methods of testing and required test results
Page 17 of 22
Guideline 1081 – Virtual Aids to Navigation
March 2010
14
ACRONYMS / INITIALISMS
AIS
Automatic Identification System
AtoN
Aid to Navigation
DGPS
Differential Global Positioning System
ECDIS
Electronic Chart Display and Information System
ECS
Electronic Chart System
EGC
Enhanced Group Calling
FATDMA
Fixed Access Time Division Multiple Access
GNSS
Global Navigation Satellite System
GPRS
General Packet Radio Service
GPS
Global Positioning System
HF
High Frequency
IALA
International Association of Marine Aids to Navigation and Lighthouse
Authorities
IBS
Integrated Bridge System
IEC
International Electro-technical Commission
IHO
International Hydrographic Organization
IMO
International Maritime Organization
INMARSAT
International Maritime Satellite Organization
ITU
International Telecommunication Union
ITU-R
ITU Radiocommunications Sector
ITU-R-M
ITU-R M series Recommendations and ITU-R M series Reports
LORAN
LOng RAnge Navigation
MF
Medium Frequency
MIO
Marine Information Overlay
MKD
Minimum Keyboard and Display
MMSI
Maritime Mobile Service Identity
MSC
Maritime Safety Committee (IMO)
MSI
Maritime Safety Information
NAV
Sub-Committee on Safety of Navigation (IMO)
NAVTEX
Navigational Telex
RAIM
Receiver Autonomous Integrity Monitoring
RCC
Rescue Co-ordination Centre
SAR
Search and Rescue
SN/Circ.
Safety of Navigation Circular (IMO)
SOLAS
United Nations Convention on Safety of Life at Sea
t.b.d.
to be decided
Virtual AtoN
Virtual Aid to Navigation
Page 18 of 22
Guideline 1081 – Virtual Aids to Navigation
March 2010
VDL
VHF Data Link
VHF
Very High Frequency
VTS
Vessel Traffic Services
VTSO
Vessel Traffic Services Operator
WiMAX
Worldwide Interoperability for Microwave Access
Page 19 of 22
Guideline 1081 – Virtual Aids to Navigation
March 2010
ANNEX 1 Application of Virtual Aids to Navigation
Application
Mode
Function
Permanent
Marking of
Obstacles
Marking
Shoals
Reefs
Permanent
Marking
(navigation
support)
Marking
of
Fairway Limits
of
and
Description
Type of Virtual
AtoN AIS
Consideration
Virtual AtoN can be
effectively
utilized
where it is difficult to
place or to maintain a
physical AtoN due to
sea state, winds or
other environmental
conditions.
A clear marking of the
shoals and/or reefs
will improve safety of
navigation
Isolated Danger
Marks & Cardinal
Marks

Virtual AtoN can be
effectively
utilized
where lighted buoys
cannot be installed for
some reason (i.e.
sharing of waterway,
separation of traffic
flow, roundabout).
Lateral Marks

Too
much
info
for
mariners
Lateral Marks, &
Safe Water Marks

Too
much
info
for
mariners
Safe Water Marks

Too
much
info
for
mariners
Lateral Marks &

Should

Integrity
monitoring
ECDIS
and
radar
reliability
A clear marking of the
fairway limits serve
for ordinary flow of
marine traffic and
improved safety of
navigation.
Marking
Fairways
of
Virtual AtoN can be
effectively
utilized
where
a physical
AtoN placement is
difficult due to the
water depth, seabed,
etc.
A clear marking of
fairway will improve
safety of navigation.
Virtual AtoN can be
effectively utilized in
approaches
to
a
harbor
entrance
where a ship changes
its course and where
it is difficult to install a
physical AtoN.
A clear marking of the
point on approach will
serve for an orderly
flow of ships at a
entrance and improve
safety and efficiency
of shipping.
Marking
of
Virtual AtoN can b
Page 20 of 22
be
Guideline 1081 – Virtual Aids to Navigation
March 2010
Fairways
&
Marking of the
Limits of Safe
Waters
effectively
utilized
where
navigation
becomes difficult due
to a thick fog, heavy
rain,
etc.
(This
application can also
be adapted as a
temporary
marking
during
a
limited
visibility.)
Safe Water Marks
temporary
Marking
of
a
recommendable
fairway during times
of limited visibility will
serve
to
improve
safety of navigation
and
efficiency
of
shipping.
Permanent
Marking
Special area (i.g.
anchorage area,
area
to
be
avoided)
Virtual AtoN can be
effectively
utilized
where pre-caution or
special
caution
required.
Special Marks

Too
much
info
for
mariners
Cardinal Marks,
Emergency
Wreck
Marks,
Isolated Danger
Mark & Special
Marks

Need to be
monitored/up
dated
Timely
deployment
required
Lateral Marks &
Safe Water Marks

A clear marking of
special
area
will
improve safety of
navigation.
Temporary
Marking
Marking of a
Navigational
Restricted Areas
Virtual AtoN can be
effectively
utilized
when
navigation
restriction is required
due to e.g., marine
accidents or when
marking of wreck or
offshore operations.

A
temporary
navigation restriction
can
prevent
subsequent incidents
from developing.
Designation of
Temporarily
Recommendable
Fairways
Virtual AtoN can be
effectively utilized for
indication of fairways
when a scale disaster
hits the area.
A clear marking of
temporarily
recommendable
fairways
will
be
expected to serve for
the
relief
ships
dispatched to the site
and to support safe
and effective relief
activities.
Page 21 of 22

Need to be
monitored/up
dated
Timely
deployment
required
Guideline 1081 – Virtual Aids to Navigation
March 2010
Marking of Aids
to
Navigation
that
are
malfunctioning
or off position
Virtual AtoN AIS can
be effectively utilized
when a physical AtoN
has lost ability to
perform
regular
functions due to a
natural disaster.
Cardinal Marks,
Lateral
Marks,
Isolated Danger
Marks,
Safe
Water Marks &
Other
Position
Marks

Timely
deployment
required
Special Marks

Timely
deployment
required
When a physical AtoN
lost ability to perform
regular functions due
to natural disasters,
recovery actions are
required
at
the
earliest opportunity.
Virtual
AtoN
can
respond
to
the
circumstance even if
the
actions
by
personnel cannot be
achieved
due
to
meteorological and/or
hydrographical
conditions, and keep
the influence of the
trouble reach to ships
in navigation at a
minimum level.
Temporary
Marking
Pilot
boarding
station
Virtual AtoN will be
useful to mark a pilot
station where position
depends
on
sea
condition.
Page 22 of 22